Circuit interrupters



Aug. 6, 1957 L. v. CHABALA 2,802,152

\ CIRCUIT INTERRUPTERS Filed Jan. 30, .1953 2 Sheets-Sheet 2 Loud Load

9 l6 H I 1- 8 WITNESSES: INVENTOR I e 4777/ Leonard V.Chobolo United States Patent CIRCUIT INTERRUPTERS Leonard V. Chabala, Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application January 30, 1953, Serial No. 334,328

6 Claims. (Cl. 317-22) My invention relates generally to circuit interrupters, and it has reference in particular to load-pickup sectionalizers.

Generally stated it is an object of my invention to provide new and novel load-pickup switch apparatus.

More particularly, it is an object of my invention to provide for adapting a sectionalizer to effect opening thereof in the usual manner in response to a fault beyond the sectionalizer and to indicate audibly such open condition, and for effecting delayed reclosing thereof following interruption of the circuit due to increased load when the circuit is reenergized after an extended outage due to interruption of the circuit because of a fault between the sectionalizer and the source.

It is one object of my invention to provide in a sectionalizer for utilizing a solenoid for closing the contacts and for reducing the magnetomotive force of the solenoid for maintaining the operating handle of the sectionalizer in the closed position when the sectionalizer is open.

Another object of my invention is to provide for using an intermittently rated solenoid on a sectionalizer for load pickup operation, and for reconnecting the solenoid in a different manner for a continuous operation so as to maintain a part of the operating mechanism in a closed position, to provide an indication of when the sectionalizer is locked open.

Yet another object of my invention is to provide in a sectionalizer for using an alternating current holding solenoid for holding at least a part of the operating mechanism in a closed position when the contacts are open, so as to produce vibrations which audibly indicate the open condition of the contacts.

In accordance with one embodiment of my invention, a solenoid is provided for operating one of a pair of overcenter toggle levers of a sectionalizer to an overcenter position to close the sectionalizer under the control of a time delay relay which operates by having a motor wind up aspring to close a set of contacts with time delay and set up a closing circuit. The spring drives an escapement which is normally prevented from operating by a voltage responsive clutch and causes the contacts to open with delay when voltage is lost, reclosing being eifected when the contacts are reclosed ata time after voltage is restored, which time is proportional to the oif time, up to a maximum of about 30 minutes. A releasable latch normally permits the toggle levers to operate to the overcenter position. It is released by a counting device to open the sectionalizer. A switch reconnects the solenoid in a difierent manner when the one lever is in the closed position, to provide for holding it there when the latch is released. Since sectionalizers are generally used on alternating current circuits, a mechanical vibration is produced by the pulsing magnetic field when the levers are out of toggle relation, which is clearly audible and indicates that the contacts are open, even though the lever is in the closed position.

For a more complete understanding of the nature and scope of my invention, reference may be made to the lCC following detailed description, which may be read in connection with the accompanying drawings, in which:

Figure 1 is a partly broken away, side elevational view in section of a sectionalizing switch embodying the principal features of my invention; a

Fig. 2 is an enlarged elevational view in section of the counter shown in Fig. 1;

Fig. 3 is a schematic view of the operating mechanism of the switch of Fig. 1 showing it in the tripped position with the toggle levers held substantially in the closed position;

Fig. 4 is a front elevational view of the sectionalizing switch of Fig. 1; and

Fig. 5 is a diagrammatic view of a portion of a distribution system showing a sectionalizing switch embodying my invention connected to operate in conjunction with a reclosing circuit breaker.

Referring to Fig. 1 of the drawings, it will be seen that a sectionalizer 17 is here shown as being enclosed within a metal tank 27, which is provided with an insulating liner 28, and which is surmounted by-a top casting 29. This sectionalizer may be substantially similar in its common parts to that described in detail in Wallace and Ogg Patent No. 2,697,149 issued December 14, 1954, in Wallace Patent No. 2,752,453 issued June 26, 1956, and in Wallace and Edwards Patent No. 2,757,321 issued July 31, 1956, which patents are assigned to the assignee of the present invention. In accordance with the showings of these applications, an incoming line 15 enters through a bushing 31 which terminates inside of the tank. The circuit then continues, through a conductor 32 to a sectionalizer coil 19. From the sectionalizer coil 19, the circuit continues through a conductor 33 which is separated from the conductor 32 by insulation 30, back underneath the bushing 31 for the incoming lead 15, and thence to the terminal 34, which constitutes one of the stationary contacts of the sectionalizer which are disposed to be engaged by a movable bridging contact 20. Ordinarily, the sectionalizer has two bushings, each with its lead passing through a bushing, and each bushing terminates, at its bottom in one of the stationary contacts of the sectionalizer, but since the drawings show an approximate central section through the sectionalizer, the second stationary contact is not visible. The movable contact -20 is shown as a contact bar or bridge, which is slidably mounted on a pull rod 36 in conjunction with a spring 21 so that it presses up against the underside of the stationary contact 34 and the other stationary contact (not shown) in the closed position of the sectionalizer, and is lowered by gravity, to operate the sectionalizer, upon the release of pull rod 36, which is shown in the form of an upwardly extending insulating tube.

The sectionalizer 17 can be made to operate either in air, in an insulating oil, or other insulating fluid. It is sometimes desirable for a counter 37 associated with the sectionalizer to operate in oil, as it involves dashpot or fluid flow operation, as subsequently described, which is somewhat more difficult to obtain in air, with the necessary time-constants. It is sometimes also desirable to have the contacts 3420 operating in oil. I have consequently illustrated this apparatus, by way of example, as having the counter 37 and the contacts 34-20 immersed in oil 40 which is contained in the tank 27.

A counter and lockout mechanism 23 is segregated, into its component parts, consisting of the counter 37 and the operating mechanism 38.

The operating mechanism comprises a bellcrank trigger 53 disposed on a bracket 54 mounted on the cover 29, to support one end of a lever 47 which is pivotally supported by a fixed pivot 48, is biased in a clockwisedirection by a spring 41 which assists in returning lever 47 to the position shown in Fig. 1 after the sectionalizer opens and carries a pivot 44 which comprises one of the terminal points of a lever 43. A toggle mechanism, including a link 46 pivotally. connected tothelever 43 by a pivot 45 and by apivot 49 to an operating handle 60 pivotally supportedon the casting 29 by a pivot 61, comprises the other terminalpoint of support for the lever 43. The pull rod 36 is connected to the lever 43 by a pivot 42. The. trigger 53 is biased clockwise by a spring 55 and has a projection 53' which engages the bracket 54 andacts as a stop. It also has a downwardly extending abutment portion 56 which is adapted to be tripped when an upward movement of a trip pin 57 of the counter 37 raises'said abutment point 56 of the trigger, whereupon the linkage of the operating mechanism permits the pull rod 36 and the movable contact member 20 to drop freely in the openingoperation of.t he mechanism. When contacts 2034 are closed, handle 60 and link 46 are in over-center toggle relation with contact 20 biased up against contacts 34 by spring 21.

p The counter 37,is suspended from the top of the top casting 29, by means of a plurality of depending insulating supports or tubes 70, which support the base frame 71 of the counter.

The counter 37 comprises, as shown in Fig. 2, a vertically disposed tube 72, which is preferably made of brass or other non-magnetizable metal. The lower end of the tube is disposed to be closed by a plug 73 of iron or other magnetic material, while the top of the tube 72 is open. The series current coil 19 surrounds a portion of the tube 72, intermediate its upper and lower ends. Immediately above the coil 19 is a perforated magnetizable plate 74. Both it and a base plate 71 are perforated so as to surround the tube 72. The plates 71 and 74 serve as the two pole pieces of an electromagnetic circuit, the excitation of which is provided by the coil 19, and are connected as by bolt 75.

Inside the tube 72 is 'a magnetizable core or armature 76, which is slidably movable, with a close fit of perhaps 3 mils radial clearance, within said tube. The armature 76 normally extends partly above and partly below the level of the upper plate 74, being located by means of a shoulder 69, in the tube, while the plug 73 is disposed partly above and partly below the base plate 71. Both the armature 76 and the plug 73 thus extend partly within and partly without the space between the two plates 74 and 71.

In accordance with the teachings of the aforesaid Wallace patent, thearmature 76 may comprise two relatively movable elements, namely, a core 77 of iron or other magnetic material having a cylindrical extension 78 at the upper end, and a movable cap or piston 80 of a non-magnetic material such as brass, closely surrounding the extension. Annular grooves 83 may be provided about the piston 80, in which may be disposed snap rings 85 of iron or other suitable magnetic material, to provide projecting magnetic ribs which are vertically spaced from each other by a spacing which is preferably approximately the same distance as the closable distance between the core 77 and the plug 73, or other such disposition which will magnetically lock the piston in its different stepped positions against unwanted vertical displacement or slippage. A snap ring 88 of magnetic material maybe disposed in a grcc-ve 87 about the tube 72 in line with the plate 74 to assist in concentrating the magnetic flux between the plate and the rings 85. A compression spring 79 is disposed between the core 77 and the plug 73, so that when the coil 19 is sufficiently energized, such as by a fault current, the core 77 is drawn downwardly towards the plug, storing energy in the interposed compression spring 79, as will be more fully described hereafter.

Both the core 77 and the plug 73 are provided with central bores 81, and the lower end of each of these bores is provided with an orifice closable by means of a H ball check valve 82, so that the fluid which is entrapped within the closed lower end of the tube 72 resists any rapid downward movement of the piston 80, because of the closing of the ball check valves 82 in the plug 73 and core 77, while the valves permit the free upward movement of the piston and core 77. The entrapped fluid could be any gas or liquid having the required vis: cosity in comparison with the mechanical clearances which are provided. The idea is to permit the respective core 77 and piston 80 to move freely upwardly, in a step-bystep motion, as will be subsequently described, while permitting them to drift back downwardly again, by fluid leakage, at a relatively slow rate.

At the top of the piston 80 is affixed an upstanding pin 84, which extends upwardly to a point above the open top end of the tube 72. This pin 84 is surrounded by a tubular tip or trip pin 57, which is capable of sewing as an adjustable vertical extension of the pin 84. This vertical adjustment is effected in any one of a plurality of vertical spaced positions corresponding to the spacing between the core 77 and the plug 73, by means of a cotterpin 86, so that adjustment may be made for any desired number of counts, such as 1, 2, 3 or 4, within the range of the counting mechanism 37.

In the operation of the counting mechanism 37, when the coil 19 is first energized with an over-current corresponding to the setting of the counter, the core 77 of the armature 76 is drawn downwardly toward the plug 73, so as to close the gap which separates the inner ends of said armature and plug. The fluid between the core 77 and plug 73 cannot move downwardly, to permit the armature and plug to come together, because of the presence of the fluid flow valve 82 in the plug 73, so the fluid between the armature and plug is forced upwardly through the check valve 82 in the core 77, and hence the piston 80 must remain still, while the core moves downwardly. The attractive force between the upper plate 74 and the upper magnetic ring is enhanced by the magnetic snap ring 88 on the tube 72, and the piston 80 is thus held securely in position as the armature 76 moves downwardly. When the coil 19 is deenergized as by the opening of a circuit breaker between the sectionalizer and the source, spring 79 forces core 77 upwardly. Because the fluid between the core 77 and piston 80 is entrapped, piston 80 moves upwardly with the core and fresh fluid is drawn into the space between plug 73 and core 77 through the orifice in plug 73. After several such counting operations, the trip pin 57 strikes the abutment 56, rotates lever 53 counterclockwise, and trips the operating mechanism 38 to open contacts 2034. Since pin. 57 is delayed in returning to its initial position by the dashpot action of the fluid in tube 72, it prevents return of lever 53 to the reset position. The weight of contact rod 36 on lever 43 causes it to rock counterclockwise about the pivot support 52 of trigger 53 as the contacts open, thus rotating lever 47 clockwise back to the position shown, assisted by spring 41. When the trip pin 57 resets, the trigger is returned to the position shown to provide a support for roller 51 of lever 47.

In order to reclose the sectionalizer after it may have been opened, a solenoid designated generally by the numeral 90 may be provided. The solenoid 90 may be supported by means of a magnet plate 98' spaced from the casting 29 by means of spacers 89, and comprise, for example, a closing solenoid coil section 92 having a tubulat sleeve 93 in which is slidably disposed a cylindrical armature 95 connected by a pin 96 to the lever 60 for pulling it downwardly into the toggle position as shown, and thereby rocking lever 43 clockwise about pivot 44 to raise the contact rod 36 and close contacts 2034. An additional solenoid coil section 91 is provided on the sleeve 93 in conjunction with the coil section 92 for holding the lever 60 in the closed position. A switch 97 may be secured by means of a bushing 94 threaded into the lower magnet plate 98 of solenoid 90, in predetermined relation .to the armature 95 for controlling energization Qfthe coil sections 91 and 92, so as to interrupt the flow of current through the closing coil section 92 and reconnect it in series with the coil section 91 to reduce the current therethrough when the sectionalizer is closed, and, in turn, set up a circuit for coil section 92 when the sectionalizer is open. The bushing 94 is inserted into sleeve 93 being threaded into plate 98 so as to be engaged by the armature 95 when lever 60 is in the closed position. The armature 95 will be resilient-1y biased against the bushing 94 when the contacts are closed by reason of the action of spring 21. However, it will be but lightly held against the bushing by the action of coil sections 91 and 92 alone, and will produce audible vibrations when the contacts are locked open, and the armature 95 is not held against the bushing firmly by the toggle action of levers 6 and 46 in conjunction with spring 21. While the solenoid is described as comprising separate coil sections, it will'be realized that a single tapped coil may readily be used.

Referring to Fig. 5, it will be seen that the sectionalizer 17 is disposed to be connected in series circuit relation with sections and 5' of a distribution circuit, with a reclosing circuit breaker 7 between the sectionalizer and a source conductor 4. The circuit breaker 7 will normally be located at-quite some distance from the sectionalizer, several loads 6 and 10, for example, being connected to conductor section 5 therebetween. The recloser has a normally closed contact 8 in series with the conductors 4 and 5, and an armature 11 which is actuated by overcurrent conditions in recloser coil 9 to separate the contacts. A counter mechanism comprises a counter member 13 which is advanced by a one-way drive represented by a pivoted lever 14, in response to opening of the recloser. A dashpot 16 operates to delay resetting of the counter member, so that after a predetermined number of opening and closing operations, usually four, the counter member advances sufficiently to lock the contact 8 in the open condition, as by releasing a suitable toggle operating mechanism 18.

The sectionalizer or sectionalizing switch 17 is shown in dot-,dash outline with its moving contact 20 connected in circuit with sections 5 and 5' of the distribution circuit. Solenoid coil 19 of the counter 37 is connected in series with the moving contact, and trip pin 57 is disposed to strike trigger 53 to release lever 43 and drop contact rod 36 to open contacts 2034 as described in connection with Fig. 1. Closing of the sectionalizer 17 is effected by connecting section 92 of the solenoid coil 90 to a source of alternating-current voltage such as the secondary 99 of a distribution or potential transformer 100 which is connected to the conductor 5. A voltage responsive time delay control relay 101 is provided for this purpose, having a motor 102 connected by suitable reduction gears '(not shown) to drive a pinion 102 and slowly rotate a lever 106 counterclockwise to actuate moving contact 103, by means of gears 104 and 105 rotatably mounted on lever 106 which is pivoted at 107 and biased clockwise by a spring 108, to complete a circuit with contact 109 for energizing coil section 92 after a time delay, if the voltage of the circuit is at least about 80 percent of its normal value. The spring 108 biases the lever 106 clockwise to elfect resetting and permit contact 103 to engage contact 110 under the control of time delay means 111, which may be of a clockwork type, and is herein represented by an escapement 112 and 112' conrliected to gear 105 by a gear train represented by gear The time delay means has retarded motion so that movement of contact 103 is delayed in resetting as well as operating. A clutch member 114 biased away from the escapement is normally made effective, being attracted to engage escapement gear 112, by voltage coil 115. When voltage is lost, the clutch member 114 is released and the spring 108 actuates lever 106 to open contacts 103-109 by driving escapement 111. When voltage restored, clutch 114 is effective and the motor 102 must run some time to rotate lever 106 counter-clockwise to actuate contact 103. Thus the operating time of the relay to reclose contacts 103-109 will be delayed in proportion to the time the relay has been deenergized, at least up to the maximum delay value of the relay.

The coil 115 is connected so as to be energized from the secondary 99 of the transformer 100. This relay may, as shown in Fig. 4, be mounted in a suitable box 116 on the top casting 29 of the sectionalizer. Normally the coil 115 is energized, so that clutch 114 prevents gear 105 from rotating, and the motor has operated gears 102' and 104 to move gear 104 to the right and urge lever 106 counter-clockwise against spring 108, to the position as shown, where it is held by clutch 114, which prevents gear 105 from rotating. The motor circuit is interrupted at contact 110, and the motor stops, it being in effect a one-way drive which prevents pinion 102' from being driven by spring 108. The circuit to the closing coil section 92 is interrupted at contacts 97b, and coil sections 91 and 92 are energized in series through contacts 97a.

When there is a fault on the distribution line, within the protective reach of an automatic reclosing circuit breaker, for example, at the point X, the recloser contact 8 thereof quickly opens, and quickly again recloses, but during the moment (12 cycles or more, in a 60-cycle line) when said recloser contact was open, the sectionalizer coil 19 is deenergized, reducing the attractive force between the armature 76 and plug 73, which were drawn together by the increased magnetomotive force of the fault current. The compression spring 79 between the core 77 and plug 73 expands, and pushes the core upward again, to the normal separation distance. During this action, however, fluid in the armature 76 is entrapped and cannot move downwardly, because of the fluid flow check valve 82 in the core 77, and hence the piston and the core 77 must move upwardly together, which they are free to do, so far as fluid-action is concerned, because the lower check valve 82 in the plug 73 will open during such movement. The magnetic attraction between the upper plate 74 and the corresponding magnetizable ring of the piston 80 of the armature 76 is now practically non-existent, because of the deenergization of the coil 19, and hence the piston 80 of the armature 76 is notched upwardly by a distance corresponding to approximately the amount of compression of the spring 79. Upon reenergization of the coil 19 above the rated value, the magnetic attraction between the adjacent ring 85 and the ring 88 serves to accurately position the piston 80 and thus correct any undershoot or overshoot.

If the fault is removed, the recloser stays closed and the counters 13 and 37 reset. However, if a fault continues on the distribution system, at the point X beyond the sectionalizer coil 19, reclosing of the recloser contact reenergizes the sectionalizer coil 19, and causes a second compression of the spring 79, in a manner already described. If the fault is still on the system, as has just been assumed, the recloser contact again opens, and a second upward stepping movement of the trip pin 57 is obtained. Thus, the step-by-step movement of the counter mechanism continues. The ring 88 about the tube 72, being of a magnetic material, acts to concentrate the magnetic flux in the gap between the plate 74 and the rings 85, thus increasing the effective locking power thereof, and accurately positioning the piston each time to prevent cumulative error.

When the last upward stepping of the piston 80 of the armature 76 is obtained, depending upon the vertical positioning of the trip pin or tubular tip 57, and usually on the third operation, this pin 57 comes into contact with the abutment 56 of trigger 53 during this last upward movement, releases the operating mechanism 38, and trips out the sectionalizer contact 20. It will be noted that this last upward movement of the trip pin 57 occurs during a time when the current in the sectionalizer coil 19 is off. In the operation of the recloser, the current remains off, that is, the recloser contact remains open for a minimum of 12 cycles (on a 60-cycle line) before the recloser contact recloses. The opening of the sectionalizer contact 20 requires something like two or three cycles, so that it is seen that the sectionalizer contact 20 opens during the current off period, so that the sectionalizer contact 20 does not have to interrupt any substantial current.

When the recloser contact 8 closes the next time, and voltage is reapplied to the conductor and loads 6 and 10, relay 101 will again be energized, and because of the relatively short duration of loss of voltage, escapement 112 will not have been driven very much and an energizing circuit will almost immediately be completed for closing coil section 92, since contact 97b is closed in the open position of the sectionalizer. The lever 60 is actuated as to close the switch, but inasmuch as trip pin 57 requires a relatively long time to reset, it delays return of trigger 53 to the initial position shown in Fig. l and the trigger 53 is not yet reset, and there is no support for the free end of lever 47. Thus, when coil 92 is energized, the lever 47 remains released, and returns to the position as shown in Fig. 3, so contact is not closed, and the switch remains locked open with the lever 60 in the closed position, and performs as an ordinary sectionalizing switch, so that the recloser 7 is effective to reenergize the distribution conductor 5. Under these conditions, coil sections 91 and 92 are energized in series through contacts 97a, and armature 95 is held in the closed position against bushing 94. Since the levers 60 and 46 are not in toggle because of contact 20 being open, the armature 95 is not forced against the bushing 94 by the spring 21, and hence is merely held there by the relatively light force of coil sections 91 and 92 in series. This permits the armature 95 to vibrate with pulsations of the alternating flux of the coil and produce an audible noise which may readily be heard from the ground, so as to provide an indication that the switch is open. Should a temporary fault occur at Y, such that the recloser 7 opens momentarily, the sectionalizer 17 will remain closed, for there will be substantially no loss of diversity in the load factor and it is not likely that the load will have increased appreciably during the relatively brief outage for one operation of the recloser. The recloser will therefore reclose and will be able to remain closed.

However, should the fault at Y be permanent, so that the recloser 7 goes through its full operating cycle of four interruptions and looks out, a relatively long time, some 20 to minutes for example, may elapse before a man is dispatched to reclose the recloser 7. During this relatively long time, it is likely that a great deal of load diversity will have been lost. Refrigerators, pumps and other intermittent loads will all be connected to the system, awaiting the return of power.

Since the recloser 7 will be open during this interval, voltage will be removed from the conductor 5, and the time delay relay 101 will have been deenergized long enough, and the clutch 114 will have been released, so that spring 108 will have slowly rotated lever 106 clockwise driving escapement 112, and relay 101 will be almost reset, it having a reset time on the order of 20 to 30 minutes, for example. Accordingly, when the voltage is restored to the conductor section 5 by closing the recloser 7, the sectionalizer switch 17 being closed, the increased current due to loss of diversity among loads such as pumps, refrigerators, etc., will usually be sufficient to cause the recloser 7 to trip out on successive reclosures, so that the interruptions of the overcurrent through the sectionalizer switch 17 cause the sectionalizer to count three openings and then look out. I

The recloser 7 may then close automatically to pick up loads 6 and 10, and will be able to stay closed, since the load current will be reduced by dropping the load beyond switch 17. When the recloser is first reclosed, voltage is applied to relay 101, but it does not have suiticient time to operate and reclose the sectionalizer before the recloser 7 opens. When the recloser recloses and stays closed,,voltage is. applied to relay 101, and when it reaches about of normal, motor 102 will run, and the relay will commence to operate to pick up the sectionalizer. Due to the accumulated time delay during the locked out time of the recloser, the relay 101 cannot immediately close contacts 103-109. During this time, the counter 37 will have returned to its reset position as shown in Fig. 1, so that it is clear of the trigger 53, and the mechanism may then reset. When the relay 101 finally closes contacts 103109 at the end of its timing period, closing coil section 92 is energized and actuates lever 60 in a clockwise direction to restore the toggle relation of levers 46 and 60, and rotate lever 43, thus raising contact rod 36 and closing switch contacts 20-34. The circuit through coil section 92 alone is interrupted when the contacts 97b of the closing relay open, and the switch is, for practical purposes, held closed by the toggle levers 60 and 46. Coil section 92 is reconnected in series with coil section 91 to limit the current therethrough.

By providing a sectionalizing switch with a closing solenoid and time delay means of the type described, I have made it possible for the continuity of service to be increased. Not only does a sectionalizing switch embodying the features of my invention provide for automatically sectionalizing the load when the current due to loss of diversity is sufiicient to cause the recloser to trip out upon closing after an extended outage, so as to enable the recloser to close and remain closed with but a portion of its initial load, but it also functions to sectionalize the load in much the usual manner when it is itself subject to the fault current. The audible vibration caused by the armature when the switch is locked open serves as an indication of this condition. A load pickup sectionalizing switch embodying the principal features of my invention is simple and inexpensive to build and is inexpensive to maintain.

While I have illustrated my invention in a particular form which is now preferred, it is to be understood that the invention is susceptible of considerable modification, by way of additions, omissions and substitution of various equivalents, without departing from the essential spirit of my invention, particularly in its broader aspects.

I claim as my invention:

1. Load pickup apparatus for an alternating-current circuit comprising, a circuit interrupter having separable contacts, operating means operable to open and close said contacts, releasable means operable to effect operation of the operating means to effect separation of said contacts, a counter advanced in response to a predetermined number of closely consecutive interruptions of an overcurrent to operate said releasable means, a solenoid for actuating the operating means, switch means normally connecting the solenoid for effecting operation of the operating means to effect engagement of said contacts, time delay means operable in response to a loss of voltage in the circuit to time the duration of the novoltage period, means including said delay means connected to effect energization of the solenoid an interval after restoration of voltage which interval is equal to the duration of the no-voltage period thus timed, in order to delay operation of the solenoid for a corresponding time after voltage is restored, and switch means operable to change the connections of the solenoid to reduce the operating force thereof when the operating means is actuated to a position for closing the contacts.

2. Load pickup apparatus for an alternating-current circuit comprising, a switch having separable contacts, a lever normally operable to open and close said contacts, releasable means operable to render the lever ineffective to close said contacts, means operable in response to predetermined current conditions to effect operation of the releasable means, a solenoid having an armature operatively connected to said lever, a time delay relay having a member slowly advanced from an initial position in response to a predetermined voltage applied to the circuit and operable in response to a loss of voltage to return slowly to said initial position so as to determine a delay period for delaying energization of the solenoid after voltage is restored which period is proportional to the time that voltage is removed, and a switch operable in accordance with the position of the lever to connect the solenoid for energization through one circuit when the lever is in a closed contact position and through another to reduce the energization thereof when it is in an open contact position.

3. Load pickup apparatus for an alternating-current circuit comprising, separable contacts biased apart, an operating mechanism for said contacts, releasable means normally maintaining said mechanism in a position with the contacts together, counting means advanced in response to closely consecutive interruptions of a predetermined value of current therethrough to release said releasable means after a predetermined number of such interruptions, electromagnetic operating means operable to effect engagement of said contacts, switch means operated by said mechanism connected in circuit with different portions of the electromagnetic means, and time delay means operable in response to the application of voltage to effect operation of the electromagnetic means with a delay proportional to the duration of loss of voltage, said time delay means having a movable contact member connected in circuit With the switch means, biasing means biasing said member slowly to one position to complete one circuit through a portion of the electromagnetic means, a motor connected in said circuit to actuate the contact member slowly to another position when voltage is present to complete another circuit including all of the electromagnetic means, escapement timing means driven by the movable member to delay movement thereof under the influence of the biasing means, and normally inoperative clutch means operable in response to the application of voltage to the circuit to stop said escapement means.

4. A circuit interrupter comprising, separable contacts, an operating mechanism including a toggle linkage for closing and opening said contacts, said operating mechanism including a lever and releasable means for preventing the toggle linkage from going into toggle and disabling the lever from closing the contacts, electromagnetic means disposed to be energized from an alternating current source operable to maintain the lever in the closed position with the contacts open and produce an audible vibration only when the releasable means is released to disable the lever from closing the contacts, said electromagnetic means including a portion disposed to be connected as a closing coil to actuate the lever to close said contacts, and switch means for changing :the connection 10 of the electromagnetic means in response to the position of the operating mechanism.

5. In a circuit interrupter, separable contacts, a lever having a resilient pivoted connection with one of the contacts, releasable means providing in one position a normal pivotal support for said lever, actuating means for said lever including a pair of levers operable to an over-center position to close sai-d contacts only when the releasable means provides said normal pivotal support, means releasing said releasable means to effect movement of said pivotal support from said one normal support position, electromagnetic means including an armature, closing means operable to actuate said armature to move said one lever to the closed position and holding means operable to maintain said armature and one lever in said closed position when the releasable means is released, and in which the armature of the electromagnetic means produces an audible vibration only when the releasable means is released and when the electromagnetic means is energized with an alternating-current voltage, said holding means including operating means for actuating one of the levers to close said contacts, and switch means for selectively energizing said holding means and closing means With an alternating current.

6. In a circuit interrupter, separable contacts, an operating mechanism for moving one of said contacts, releasable means operable to release the contacts from a closed position and remain released for a predetermined time, a counter operable to release said releasable means, electromagnetic means connected to the operating mechanism for effecting operation thereof in a direction to close said contacts whenever voltage is applied to the electromagnetic means, said electromagnetic means being operable to produce an audible vibration only when energized during the time the releasable means is released to prevent reclosing of the contacts, and means including time delay means connecting the electromagnetic means for energization a time after voltage is applied to the circuit which time is proportional to the time voltage has been off.

References Cited in the file of this patent UNITED STATES PATENTS 599,344 Murphy Feb. 22, 1898 735,170 Steward, Jr. Aug. 4, 1903 954,745 Larsen Apr. 12, 1910 1,915,951 Pinkham June 27, 1933 1,957,734 Seese May 8, 1934 2,041,903 Cole May 26, 1936 2,049,308 Miles July 28, 1936 2,068,620 Spurgeon Jan. 19, 1937 2,145,141 Starr Jan. 24, 1939 2,515,530 Schindler July 18, 1950 2,528,197 Wallace Oct. 31, 1950 2,563,136 Schindler Aug. 7, 1951 2,697,149 Wallace et al Dec. 14, 1954 2,701,828 Edwards et a1 Feb. 8, 1955 

